Ceiling illuminating system



June 18, 1963 M. H. KRUGER 3,094,285

CEILING ILLUMINATING 5 15mm Filed June 27, 1960 s Shegts-Sheet 1 June18, 1963 M. H; KRUGER CEILING ILLUMINATING' SYSTEM 3 She at s-Sheesl'. 2

Filed June 27-, 1960 June 18 1963 M. H. KRUGER ,09

- CEILING ILLUMINATI'NG SYSTEM Filed June 27. 1960 s Sheets-Sheet s J!1% Q :1- J

J LVJ I Li J United States Patent 6 3,094,285 CEILING ILLUMINATINGSYSTEM Michael Henry Kruger, Chestnut Hill, Mass., assiguor toSmithcraft Corporation, Chelsea, Mass., a corporation of MassachusettsFiled' June 27-, 1960, Ser. No. 39,058 18 Claims. (Cl. 240-9) Theinvention relatesto lighting at ceilings and more particularly tolighting assemblies adapted to be mounted below overhead structure in.rooms.

The apparent, visible ceilings of present-day rooms have been disposedconsiderably below the structural overhead when providing for airconditioning (including coolingand heating), and air ducts, and otherservices such as electrical power, telephone wiring and sprinklingsystems are placed in the cavity thus defined; above the apparentceiling. and lighting means associated therewith.

Similarly, when it is desired to avoid having pendant light fixtureshanging down from the visible ceiling, while employing relativelyinexpensive acoustical sheet for sound damping/the common practice hasbeen to suspend the acoustical sheet across the room to define a planarceiling, well below the structural overhead, and lighting fixtures havebeen recessed into-the cavity.

While the dirt catching and unsightly pendant fixtures are thuseliminated, such has been achieved with a ceiling comprised ofalternating,- brilliantly-lighted Zones, where the recessed lightsappear, and dark zones, comprised of opaque, acoustical sheet. Thiscreates risk of eyestnain toroom occupants. Such ceilings have beenconsidered to be so unattractive and otherwise unsuitable that luninousceilings have been frequently employed, which'are more expensive,and have often required more cavity space.

To provide a building with a given apparent ceiling height, buildingcosts obviously greatly increase Withincrease of the depth of the deadcavity, and these costs are especially great where air conditioningisprovided and whererelatively more expensive ceiling arrangements areemployed rather than opaque, acoustical sheet. Many existing buildingswithlow structural ceilings cannot prac tically be modernized alongthelines suggested above.

A principal objective of the. invention is, therefore, the provision ofceiling assemblies which overcome the above mentioned disadvantages ofthe prior art. More particularly the invention has as one objective thedecrease in needed cavity space in a well-illuminated, air condi tionedroom. Another objective is the better utilization of acoustical sheetmaterial, so. that it forms an attractive and functional secondarysource of illumination, and the over-all ceiling is devoid ofeyestnaining large contrasting brightness regions. Another objective isincrease in. apparent ceiling height in a room having an acousticalsheet ceiling and no pendant light fixtures.

Other objectives include providing a grid assembly of a strong and rigidconstruction having a number of integrated functions to achieveinexpensive, small cavity, combinations. of even illumination, airconditioning, ready partitioning and acoustical damping; and a gridcoupling means permitting rapid, economical, rigid and accurate onssiteassembling.

These and other objects and features of the invention will be more.fully appreciated with consideration of the following detaileddescription and drawings.

In the drawings:

FIG. 1 is a partially cutaway perspective looking down upon a portionofoneembodiment of the ceiling according to the invention;

FIG. 2 is a partially exploded view of a portion of the ceilingof:.FIG.. 1, illustrating the relationship. of light and. correspondinglight shield;

FIG. 3 is a section of the ceiling of FIG. 1 taken on lines 3-3;.

FIG. 3a a View similar to FIG. 3 of, another preferred embodiment;-

FIG. 4 is a partiallyexploded; view on an enlarged scale of theinterconnection of a juncture of grid members in the ceiling of FIG. 1;

FIG. 5' is asectionof a juncture of 4 grid members as Occurs in; centralportions of the ceiling;

FIG. 6; is a View similar. to; 5 of the juncture of 3' gridmembersasoccursat the sides of the ceiling;

FIG. 7 is. a view similar to; FIGS. 5 and. 6, illustrating a corner of,the grid assembly;

FIG. 8 isillustnative of a novel, grid member adapted to serve asacoustical. sheet support, as a, light reflector and cutoff, and asanair register;

FIG. 9 is a view from below of a. variation of the system of FIG. 1wherein grid membersparallel with the tubular light are of substantialvolume similar to the grid, members of FIG. 8, and: in which successivegrid members are inv end-to-endcommunication serving as ducts for,transmission of air aswell as providing air registers;

FIG. 10 is a partially cutaway view from below of the integratedilluminated ceiling, of FIG. 1.

The present-daycommonlow-cost acoustical sheet ceilings noted above havebeen comprised of a suspended metal frame upon which acoustical sheethas rested generally'flush the-lower surfaces of the framework. Atspaced intervals. fluorescent light fixtures have been recessed. withlamp holders, lamps, and wiring well above the plane ofthe apparentacoustical ceiling. Such ceilings are dark, with bright areas only wherethe recessed lights occur. This. results. in eyestrain due to thevariations in the ceiling brightness level. There is an inefficient useof light and. poor appearance. In accordance with the teachings of theinvention herein utilizing generally the same kinds and quantitiesofmaterials, there is provided a ceiling having a generally uniformbrightness level illuminating the room below. There is achieved aceiling, which, from: a standpoint of illuminationis competitivelysimilar to the relatively very expensive lighting systems known asluminous ceilings. Moreover, a substantial, increase in apparent ceilingheight is achieved.

Referring to the preferred embodiment of FIG. 1, grid 20 is formed by amultiplicity of parallel, elongated grid members 24' suspended by wires26 from overhead structure, connected with similar cross-grid members22.

Each grid member is: provided with horizontal upper ledges 28 and ledges29 which may be divided in the center by upstanding longitudinal ribs 30having spacedpart holes through which the supporting wires are secured,or may be smooth as suggested by the form of cross-grid member ledges29, and supported by wires, vertical pipes or other such means engagingthe grid members at the ledges or otherwise. Sheets 32 of acousticalmaterial, e.g. sound-absorbent fiber, which may be acoustical board,rolled batting or other sheet means are horizontally disposed, supportedat least in part by the ledges. Where employed, ribs 30 promotepositioning of the sheets, during. assembling.

A plurality of fluorescent light tube means 34 are supported betweenpairs, of grid members 2.4-, parallel therewithv below ledges. 28. and29 and sheets 32. In the efiicient use of materials of the embodiment ofFIG. 1, cross-gridmembers22, positioning grid members. 24 also supportvends of the light tube means.

Each light tube means is comprised of at least one tubularfluorescentbulb 36' and appropriate electrical connections, e.g. opposedlamp holders and a formed metal strip 38, carrying ballast and wiring.In this preferred embodiment the metal strip provides ledges 31 whichmay be similar to ledges 28, 29 for support of sheet 32. An elongatedclosure 39 overlies and closes the strip 38.

A light-shielding member 40 comprised preferably of optically treatedplastic is disposed below each bulb 36 and is likewise preferablysupported by opposed cross grid members 22. The light-shielding members40 extend longitudinally with the bulbs and have a substantiallytransverse dimension, relative to the bulb, with each longitudinalextremity 41 thereof disposed substantially to the side from thecorresponding side of the bulb. The longitudinal extremities 41 can becomprised of integral, upturned portions, with overlying margins adaptedto rest upon supporting pins 42 held by cross grid members 22, see FIG.2. The light-shielding member has a retracting characteristic, thehorizontal surface directs incident light steeply downward, and theupturned sides direct light toward the grid members 24.

The grid members 24 are provided with downward extending, longitudinalsurfaces 25 parallel with the fluorescent tubes 36.

Referring to 'FIG. 3, the lower longitudinal edges of grid memberdownward-extending surfaces 25, the lon gitudinal edges oflight-difiusing shields 40 and the bulbs 36 are aligned as indicated sothat rays from the bulb passing laterally, clear of the light-shieldingmember impinge either upon grid member surfaces 25 or the undersurfaceof sheets 32, hence no bare bulb is exposed to view from below. The gridmember surfaces 25 and the undersurface of the acoustical sheets 32 areprovided with a light-reflecting finish, and, being thus illuminated bythe light tube means, provide secondary illumination to the room, in aceiling of generally even brightness. The shielding member may transmitdirect relatively high level illumination, but in rays at such steepangles that they are not observable in looking at the ceiling withnormal angles of view.

Both grid members 24 and the cross-grid members in this preferredembodiment are box-formed sheet metal channels defining longitudinalpassages through which wiring can be easily run, and providedouble-walled sound barriers.

The hollow box cross section of the grid members makes the grid membersrigid, self-supporting, and uniquely adapted to be interengaged withcouplers to provide a strong, rigid and accurately aligned ceiling grid,as hereafter discussed with reference to FIGS. 4-7.

Referring to FIG. 3a, grid members 24 have downwardly extending, opposedsurfaces 25' flaring outwardly from narrow undersurface 27, either flator rounded, the only portion not exposed to direct light. Indeed, insome instances this could be a V point in cross section, eliminatingeven this thin line of shadow, but the thin shadow line gives adesirable texture to the ceiling, permits substantial volume to beenclosed by the grid member, important for instance for passage of airas hereafter described, and does not cause eyestrain.

The light means here comprises a pair of light tubes 36 and thelight-shielding member 40' comprises a planar-diffusing member comprisedof vertically arranged, intersecting strips 47. It will be noted thatthis lightshielding member is open permitting air to pass therethroughand the above acoustical sheet is thus advantageously exposed to soundfor damping. Each grid member along a bulb serves as a light cutofi.Lower horizontal edge 29 of each of such grid members is on a line ofsight with the lateral extremity of the light-shielding member 40,intersecting the horizontal at an angle A. A line of sight between thatlight-shielding member extremity and the upper limb 37 of the adjacentlight means intersects the horizontal at smaller angle B, henceeyestraining bare bulb is not visible from below, between thecorresponding edges of the shielding member and the grid member. Where,however, the comfort requirements of a room require that only lightradiated at slight angles to the horizontal be cut off, or whererelatively close spacing of parallel grid members 24 or 24 can beemployed, e.g. to house building services as hereafter discussed, thegrid members 24 are employed alone, without light-shielding members, andserve as light cutoffs as suggested by the cutaway of FIG. 3a. Indeed,cross-grid members 22 similarly serve to promote comfort by lightcutoff, and the grid alone will block all direct light radiating towardsremote points on the floor below, and hence is particularly advantageousin very large, low ceilinged rooms.

The undersurface of the right hand grid member in this figure isprovided with an elongated, downwardly extending rib 35 engaged with amatching groove in the head of wall partition 45, positioning andsecuring it.

Referring to FIGS. 4-7, central coupler 46, side coupler 48 and cornercoupler 50 each is provided with plug portions 52 adapted to engageinternally end-connected grid members 24 and also cross-grid members 22,see FIG. 4. These plug portions have perimeter dimensions substantiallythe same as the internal dimensions of the grid members. Plugs on eitherside of one plug provide abutment shoulder means adapted to be abuttedby grid member and engaging that plug. Each plus has a substantialoutward extent in contact with corresponding inner surface portions ofits grid member. Thus a fivesided snug fit between a grid member end andits coupler is achieved. They are locked together by means of tabs 58struck from portions of the grid member, preferably ledge 28, overlyinga hollow horizontal end of the coupler. During assembling these tabs arebent into the hollow of the coupler and interior edge 60 of each of thetabs engages the inner surface 57 of the plug end, locking coupler andgrid member from relative movement. Thus adjacent grid members arerigidly and rapidly locked together during on-site assembling.

Holes 55 are provided in plug ends providing, when desired,communication between grid members at the connections. While shown to beoval, adequate for low air flow, where higher flows are involved theholes are shaped to minimize air flow resistance and sound, An insert 59(see FIG. 10) is inserted in the bottom hollow end of each coupler toenhance appearance, and for air sealing. It will be appreciated thatsince a large number of grid members are advantageously employed in aroom, the air flow through each can be small, hence pressure drop andnoise will be minimized, and dirt discoloration at the outlets avoided.The unique couplers are adapted to turn the air from grid members 24 tocross-grid members 22, hence air distribution can be in any desiredpattern, and can be changed as needed when the room partitioning isrearranged. Thus there are important functions the grid members performin addition to the serving as light cutoff and together with the sheet32, serving as source of secondary illumination. As in FIG. 8 a gridmember 60 is provided with perforated sides and an air duct 70 isconnected from above, and the grid member serves as an air register. Theupper portions of these grid members are quite wide providing asubstantial air capacity. The downward extending sides 72 convergeinwardly to a relatively narrow undersurface 74. As these sloped sidesare exposed to lllumination, dark ceiling portions are limited to thenarrow ceiling texturing undersurfaces While a large grid member volumeis achieved.

Referring to FIG. 9 grid members have substantially the same crosssection, but here serve as air ducts as well as being provided with airregister means including air register grilles 82 and opening 83 in thegrid sides, transmitting air across the room to outlets. Couplerssimilar to those described above are employed, air passage holes beingprovided in the coupler plug-end walls inserted in duct grid members.

Referring to FIG, 10, it will be appreciated that the ceiling of theinvention achieves an apparent ceiling height which is virtually theuppermost extent of the assembly itself. Thus it is possible to avoidwaste cavity space, and

to lower the structural overhead in new construction, a

achieving substantial savings in building materials. For the first timeit is now practical to modernizeold low ceiling buildings in arelatively inexpensive manner. From the view of FIG. '10, it will alsobe appreciated that ll'OOIl'l partitions of a thickness equal to thegrid members 22, 24 can be set in place throughout the room, reaching tothe ceilingwith no changes in the ceiling lighting being necessary. Suchpartitions are anchored at the top to grid members adapted to thepurpose, see FIG. 3a. It

will also be appreciated that the bulbs are exposed forintercommunication speaker system adapted to play music,

complete with wiring can be installed. Special high intensity spotlights can be installed and wired. And very importantly, a low flow,even air distribution system is provided, which uniquely can be changedto adequately ventilate cubbyholes partitioned oil, whenever desired,and all of this is achieved with a ceiling that can in fact be thestructural overhead, to which can be applied a sheet of sound dampingmaterial.

It will be understood that the foregoing are descriptions anddrawings-of preferred embodiments and various details thereof can bemodified within the spirit and scope of the invention.

I claim:

1. .An illuminating, sound-absorbent ceiling comprising a multiplicityof elongated grid members adapted to be suspended horizontally fromoverhead structure, each grid member being provided with an elongatedupper surface, acoustical sheet means having a light reflective lowersurface disposed over and supported at least in part by said grid memberupper surfaces, at least some of said grid members being spaced apartfrom and parallel with adjacent grid members forming a plurality of gridmember pairs, a plurality of elongated light tube means, meanssupporting each light tube means between a said pair of grid members andparallel therewith below said lower surface of said acoustical sheetmeans, each grid member disposed along the side of a light tube meanshaving a generally continuous surface parallel with the correspondinglight tube means and extending downwardly to a lower horizontal edgebelow said light tube means, a plurality of light-shielding means, onedisposed below, along the length of each light tube means, eachlightshielding means being substantially narrower than the space betweenthe grid members of the corresponding pair but wider than thecorresponding light tube means, having each longitudinal upper edgespaced aside from the corresponding side of said light tube means, eachlight tube means, its light-shielding means, and the corresponding pairof grid members being relatively positioned so that a line of sightthrough each light-shielding means longitud-inal upper edge and thelower inner edge of the corresponding grid member intersects thehorizontal at an angle no less than that of a line of sight between thatshielding means edge and the upper limb of the corresponding light tubmeans.

2. The ceiling of claim 1 wherein at least some of said grid membersdefine hollow longitudinal chambers, each provided with an air inletmeans and an air outlet means, thereby serving as a portion of the airservice system.

3. The ceiling of claim 2 wherein the air inlet means of some of saidhollow grid members comprise other of said hollow grid members in directend communication therewith.

4. The ceiling of claim 2 wherein the outlet means of at least one ofsaid grid members is an air register means provided in a longitudinalwall of said grid member.

5. The ceiling of claim 1 wherein a plurality of said light tube meansare disposed in a parallel relationship across said ceiling, spacedalternately with parallel grid members, those grid members positionedbetween light tube means being shared grid members providing twogenerally oppositely directed, downwardly extending surfaces, onedisposed toward each of said light tube means.

6. The ceiling of claim 5 wherein at least some of said shared gridmembers have two spaced-apart walls providing said two downwardlyextending surfaces, said grid members further being provided withadditional longitudinal, enclosing wall portions, thereby defininghollow gn'd member enclosures adapted to serve as a housing for buildingservices.

7. The ceiling of claim l1 wherein said light-shielding means comprisesan optically treated plastic member having a horizontal surface portionadapted to retract light steeply downwards, and having upstanding sideportions comprising the lateral extremities adapted to refract lighttowards corresponding grid member downwardly-extending surfaces.

8. The ceiling of claim 1 wherein undersurfaces of at least some of saidgrid members are each provided with a longitudinal engagement means,adapted to engage with the upper edge portions of room partitions forpositioning adapted to be disposed in a horizontal plane, each gridmember having a longitudinal surface extending downwardly to ahorizontal lower longitudinal edge, a generally planar sound-absorbentmeans disposed horizontally at a level above said grid member surfacesand positioned between them, the lower surface of said soundabsorbentmeans being light-reflective, an elongated light tube means mountedparallel with and between said grid members, below said sound-absorbentmeans and above said lower longitudinal edges of said grid members, andan elongated light shielding means disposed under said light tube means,said shielding means being adapted to prevent the transmission ofglaring direct light into the eyes of persons below said ceiling, saidshielding means being wider than said light tube means but narrower thanthe space between said grid members leaving portions of saidlight-reflective surface of said sound-absorbent means unshielded, thelongitudinal edges of said shielding means being spaced outwardly fromthe corresponding s ides of said light tube means, said light tubemeans, its light-shield means and said grid members being relatively postioned so that a line of sight through each longitudmal upper edge ofsaid light-shielding means and the lower longitudinal inner edge of thecorresponding grid member intersects the horizontal at an angle no lessthan that of the line of sight between that shielding means edge and theupper limb of the light tube means.

10. The ceiling of claim 9 wherein said unshielded portions of saidlight-reflective surface of said soundabsorbent means are exposed todirect upwardly traveling rays of light from said light tube means.

11. The ceiling of claim. 9* wherein at least one of said grid membersadjacent said elongated tube means and in said line of sight alignmentwith said light-shielding means is hollow defining a longitudinalpassage, said grid member being provided with an air inlet means and anair outlet means.

12. The ceiling of claim 9 wherein at least one of said grid members ishollow, having an air register means provided in a longitudinal surfacethereof, said one grid member being connected to and in communicationwith at right angles thereto, a plurality of elongated light tube meanseach parallel with and between a pair of parallel grid members of saidfirst group, supported by grid members of said second group extending atright angles thereto, the parallel grid members of said first groupadjacent said light tube means each having a generally continuoussurface parallel with its light tube means and extending downwardly to alower longitudinal horizontal edge below said light tube means, at leastsome of said grid members being hollow and adapted to convey air forventilation, the outer surfaces of the grid members of said first groupdirected toward said light tube means being light-reflective, each lighttube means having a parallel elongated light shield means disposed underit, each said light shield means being narrower than the spacing betweenthe grid members of said first group lying adjacent thereto, and beingwider than the corresponding light tube means, the longitudinal upperedges of said shield means spaced outwardly from the corresponding sidesof said light tube means, each light tube means, its light shield meansand the corresponding parallel pair of grid members of said first groupbeing relatively positioned so that a line of sight through each lightshield means longitudinal upper edge and the lower longitudinal inneredge of the corresponding grid mem- '8 her intersects the horizontal atan angle no less than the line of sight between that shield means edgeand the upper limb of the corresponding light tube means.

15. The ceiling assembly of claim 14 wherein ends of hollow grid membersare connected together with the volume of one in communication with thevolume of another, one grid member connected to a source of ventilatingair and discharging into the other grid member in communicationtherewith.

16. The ceiling assembly of claim 14 wherein at least some of saidhollow grid members each is defined by relatively rigid thin wallsproviding a narrow undersurface, opposite, outwardly flaring side walls,and an upper longitudinal closing surface means cooperating to provide aceiling of generally even brightness while providing a large air passagecross section.

17. The ceiling assembly of claim 14- wherein each of said grid membersis provided with an upper supporting surface for supporting overlyingacoustical sheet means.

18. The ceiling assembly of claim 16 wherein at least some of said gridmembers have undersurfiaces each defining an elongated engagement meansadapted to engage for positioning and support upper edge portions of runpartitions.

References Cited in the file of this patent UNITED STATES PATENTS2,097,580 Tarbell Nov. 2, 1937 2,659,807 Wakefield Nov. 17, 19532,659,808 Beckwith Nov. 17, 1953 2,781,110 Weller et al Feb. 12, 19572,803,741 Guth Aug. 20, 1957 2,833,199 Wakefield May 6, 1958 2,888,113Schwartz et al May 26, 1959 2,956,150 Schwartz et al. Oct. 11, 1960

1. AN ILLUMINATING, SOUND-ABSORBENT CEILING COMPRISING A MULTIPLICITY OF ELONGATED GRID MEMBERS ADAPTED TO BE SUSPENDED HORIZONTALLY FROM OVERHEAD STRUCTURE, EACH GRID MEMBER BEING PROVIDED WITH AN ELONGATED UPPER SURFACE, ACOUSTICAL SHEET MEANS HAVING A LIGHT REFLECTIVE LOWER SURFACE DISPOSED OVER AND SUPPORTED AT LEAST IN PART BY SAID GRID MEMBER UPPER SURFACES, AT LEAST SOME OF SAID GRID MEMBERS BEING SPACED APART FROM AND PARALLEL WITH ADJACENT GRID MEMBERS FORMING A PLURALITY OF GRID MEMBER PAIRS, A PLURALITY OF ELONGATED LIGHT TUBE MEANS, MEANS SUPPORTING EACH LIGHT TUBE MEANS BETWEEN A SAID PAIR OF GRID MEMBERS AND PARALLEL THEREWITH BELOW SAID LOWER SURFACE OF SAID ACOUSTICAL SHEET MEANS, EACH GRID MEMBER DISPOSED ALONG THE SIDE OF A LIGHT TUBE MEANS HAVING A GENERALLY CONTINUOUS SURFACE PARALLEL WITH THE CORRESPONDING LIGHT TUBE MEANS AND EXTENDING DOWNWARDLY TO A LOWER HORIZONTAL EDGE BELOW SAID LIGHT TUBE MEANS, A PLURALITY OF LIGHT-SHIELDING MEANS, ONE DISPOSED BELOW, ALONG THE LENGTH OF EACH LIGHT TUBE MEANS, EACH LIGHTSHIELDING MEANS BEING SUBSTANTIALLY NARROWER THAN THE SPACE BETWEEN THE GRID MEMBERS OF THE CORRESPONDING PAIR BUT WIDER THAN THE CORRESPONDING LIGHT TUBE MEANS, HAVING EACH LONGITUDINAL UPPER EDGE SPACED ASIDE FROM THE CORRESPONDING SIDE OF SAID LIGHT TUBE MEANS, EACH LIGHT TUBE MEANS, ITS LIGHT-SHIELDING MEANS, AND THE CORRESPONDING PAIR OF GRID MEMBERS BEING RELATIVELY POSITIONED SO THAT A LINE OF SIGHT THROUGH EACH LIGHT-SHIELDING MEANS LONGITUDINAL UPPER EDGE AND THE LOWER INNER EDGE OF THE CORRESPONDING GRID MEMBER INTERSECTS THE HORIZONTAL AT AN ANGLE NO LESS THAN THAT OF A LINE OF SIGHT BETWEEN THAT SHIELDING MEANS EDGE AND THE UPPER LIMB OF THE CORRESPONDING LIGHT TUBE MEANS. 